Other layered inorganic hosts

Alkali metals can be intercalated into MPS3 either by chemical or electrochemical techniques. Chemical intercalation takes place when the host is reacted with an organo-alkali metal compound such as n-butyllithium or sodium napthalide. The reaction with n-butyllithium can be represented as  

The optical properties of MPS3 and Li,MPS3 have been studied. The host phases are broad-band semiconductors with band gaps of 1.3-3.5 eV. The three compounds that are electrochemically active are NiPS3, FePS3 and FePSe3, which possess the smallest band gaps. Upon intercalation with lithium, the transmittance decreases until the 

Magnetic susceptibility and Li and magnetic resonance results of FePSj and their lithium intercalates reveal that iron remains in the high-spin divalent state. In Li NiPSj, electrons added by intercalation of lithium seem to go to the transition-metal 4s or higher empty sulphur orbitals. The disappearance of magnetism in Li NiPSj for x 0.5 is not understood. 

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Organic molecules such as aniline, pyrrole and 2,2 -bithiophene have been intercalated and polymerized within the galleries of clay minerals, FeOCl, V2O5 gel and other layered hosts to yield multilayered inorganic/organic polymer nanocomposites... 

The electrochemical intercalation/insertion is not a special property of graphite. It is apparent also with many other host/guest pairs, provided that the host lattice is a thermodynamically or kinetically stable system of interconnected vacant lattice sites for transport and location of guest species. Particularly useful are host lattices of inorganic oxides and sulphides with layer or chain-type structures. Figure 5.30 presents an example of the cathodic insertion of Li+ into the TiS2 host lattice, which is practically important in lithium batteries. 

Interpolation or intercalation (see Intercalation Chemistry) is said to occur when additional species are placed into a host stmcture to change either composition or properties. At one extreme, intercalation can refer to the insertion of gnest molecnles into cage stmctures such as that of the zeolites (see Zeolites), or between the layers of laminated compounds snch as the clays (see Silicon Inorganic Chemistry). At the other extreme, the insertion of small atoms snch as C or N into metal phases to form interstitial alloys (see Alloys Carbides Transition Metal Solid-state Chemistry Nitrides Transition Metal Solid-state Chemistry), is inclnded in the category. A large variety of stmctures can be found in snch materials, and... 

The diversity of the inclusion of molecules of any type into host lattices which are distinctly inorganic is now becoming apparent [31], Apart from the oxidic zeolites, aluminosilicates and derivatives with other tetrahedral sites, there are the layered silicates and minerals, pillared clays and numerous other intercalation and inclusion systems, including graphite, metal sulfides and metal cyanides [23, 32, 33]. 

The symposium was held at Hoshi University in Tokyo. Due to the multidisciplinary nature of the subjects treated, the scope and subjects were grouped into two parts. In the first group, the chemistry of cyclodextrins, synthetic organic hosts, inorganic and metal complex hosts and layered hosts were treated. In the second group applications in various fields, biomimetic aspects, physicochemical aspects, selectivity, stereo-specificity and other aspects were discussed. The scientific sessions were carried out in a really vivid atmosphere. The number of participants viz 50 from 19 overseas countries and 253 domestic participants exceeded our expectation. 

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